1. Field of the Art
The present invention relates to a cover-tape feeding apparatus which feeds a cover tape as an element of a carrier tape carrying electric components (e.g., electronic components); a cover-tape treating apparatus which treats a cover tape; and an electric-component feeder which supplies electric components.
2. Related Art Statement
There is known a carrier tape which includes (a) an accommodating tape having, at a predetermined pocket pitch, a plurality of pockets accommodating a plurality of electric components ("ECs"), respectively, and (b) a cover tape attached to the accommodating tape to close the pockets, and which is fed in a lengthwise direction thereof at a carrier-tape-feed pitch equal to a quotient obtained by dividing the pocket pitch by an integral number. A portion of the cover tape is peeled from the accommodating tape, and the peeled portion of the tape is fed by a cover-tape feeding device.
The cover tape peeled from the accommodating tape may be treated in various manners. For example, Japanese Patent Application laid open for public inspection under Publication No. 7(1995)-101409 discloses a cover-tape treating device which peels a cover tape from an EC-accommodating tape and takes up the cover tape onto a take-up reel. Otherwise, a pair of rotatable rollers may be used such that the two rollers cooperate with each other to pinch a cover tape, and are rotated to feed the cover tape while peeling it from an EC-accommodating tape. In the latter case, the cover tap peeled and fed by the rollers is taken up by a take-up roller, or is collected by a cover-tape collecting box.
However, in the case where a take-up reel takes up a cover tape peeled from an EC-accommodating tape, the diameter of the cover tape wound around the take-up reel increases as the amount of the cover tape taken up by the reel increases. Therefore, a length of the cover tape taken up by a unit angle of rotation of the take-up reel increases. On the other hand, a length of the cover tape peeled from the EC-accommodating tape by one carrier-tape feeding operation does not change. To solve this problem, the cover-tape treating device disclosed in the above-indicated document is constructed such that after a certain length of the cover tape has been peeled from the EC-accommodating tape, a tension force exerted to the cover tape in a direction opposite to a direction in which the cover tape is taken up exceeds a drive force of a drive lever to drive or rotate the take-up reel, so that the reel is prevented from being rotated over an excessive angle. However, as the diameter of the cover tape being taken up on the take-up reel increases, the tension force exerted to the cover tape being peeled from the EC-accommodating tape fluctuates, which leads to unstable peeling of the cover tape from the accommodating tape, even breakage of the cover tape.
Meanwhile, in the case where a pair of rotatable rollers pinching a cover tape feed the cover tape while peeling the tape from an EC-accommodating tape, a length of the cover tape peeled by a unit angle of rotation of the rollers does not change. Therefore, this case is free from the problem with the case where a take-up reel takes up a cover tape, that is, the problem of unstable peeling of the cover tape from the EC-accommodating tape. However, it is difficult to treat the peeled cover tape. For example, in the case where the peeled cover tape is taken up by a takeup reel or is collected by a collecting box, the cover tape is fed in a free state from the rollers to the reel or the box, which may lead to jamming of the cover tape.